Methods for electrostatic coating of an abluminal stent surface

Abstract

A stent mandrel fixture for supporting a stent during the electrostatic application of a coating substance is provided.

1. A method for spraying an outer surface of a stent with a coating substance, comprising the steps of:
 providing a stent in conductive contact with a first mandrel component supporting the stent and applying a charge to the stent and/or grounding the stent, wherein an end portion of the first mandrel component supports the stent, and the end portion includes a non-conductive sleeve, a non-conductive coating or the end portion is made from a non-conductive material; 
 disposing a second mandrel component at least partially within a bore of the stent, the second mandrel component being spaced from the walls of the bore, the second mandrel component including an outermost surface exposed to at least a portion of the walls of the bore and being made from a nonconductive material or being coated with a nonconductive material; 
 charging a coating substance; and 
 spraying the stent with the charged coating substance. 
 
     
     
       2. The method of  claim 1 , wherein the second mandrel component includes an outermost surface exposed to all of the walls of the bore. 
     
     
       3. The method of  claim 1 , wherein the stent has a first and second end being supported by respective first and second end portions of the first mandrel component, wherein the first end portion is made from a non-conductive material, or is insulated with a non-conductive sleeve or a coating and the second end portion provides the conductive contact between the first mandrel and stent. 
     
     
       4. The method of  claim 1 , wherein the end portion includes a conductive part for forming the conductive contact with the stent and a segment comprising a non-conductive sleeve, a non-conductive coating or a non-conductive material. 
     
     
       5. The method of  claim 1 , wherein the non-conductive material or coating is patterned so as to provide areas where a conductive material of the second mandrel is exposed to the stent so as to selectively coat designated areas of an inner surface of the stent. 
     
     
       6. A method for spraying an outer surface of a stent with a coating substance, comprising the steps of:
 providing a stent in conductive contact with a first mandrel component supporting the stent and applying a charge to the stent and/or grounding the stent; 
 disposing a second mandrel component at least partially within a bore of the stent, the second mandrel component being spaced from the walls of the bore, the second mandrel component including an outermost surface exposed to at least a portion of the walls of the bore and being made from a nonconductive material or being coated with a nonconductive material; 
 charging a coating substance; and 
 spraying the stent with the charged coating substance; 
 wherein the second mandrel component includes an outermost surface exposed to only a portion of the walls of the bore. 
 
     
     
       7. The method of  claim 6 , wherein the outermost surface of the second mandrel extends beyond the length of the stent. 
     
     
       8. A method for applying a composition to a stent, comprising the steps of:
 applying a charge to the stent and/or grounding the stent; 
 ionizing a composition; 
 disposing a mandrel component within a bore of the stent, the mandrel component having an outermost surface spaced from and exposed to a luminal surface of the stent and an electric field extending from the outermost surface and having the same polarity as the ionized composition; and 
 spraying the stent with the ionized composition including limiting or preventing composition from coating the luminal surface of the stent by the electric field repelling the ionized composition; 
 wherein the stent is supported at only one end by the mandrel component. 
 
     
     
       9. The method of  claim 8 , wherein the mandrel component carries the same charge as the ionized composition. 
     
     
       10. The method of  claim 8 , wherein the stent is rotated and/or translated as the stent is sprayed with the ionized composition. 
     
     
       11. The method of  claim 8 , wherein the stent is coupled to a power source, further including using the power source to maintain a neutral charge on the stent or maintain a charge opposite of the ionized composition during the spraying step. 
     
     
       12. The method of  claim 8 , further including the step of applying a voltage sufficient to both atomize and ionize the composition. 
     
     
       13. The method of  claim 8 , further including the step of atomizing the composition using an air-assisted atomization nozzle and power source. 
     
     
       14. The method of  claim 8 , wherein the stent is crimped or friction fit to the mandrel component. 
     
     
       15. A method for applying a composition to a stent, comprising the steps of:
 applying a charge to the stent and/or grounding the stent; 
 ionizing a composition; 
 disposing a first mandrel component within a bore of the stent, the first mandrel component having an outermost surface spaced from and exposed to a luminal surface of the stent and an electric field extending from the outermost surface and having the same polarity as the ionized composition; 
 spraying the stent with the ionized composition including limiting or preventing composition from coating the luminal surface of the stent by the electric field repelling the ionized composition; and 
 disposing a second mandrel component at least partially within the bore of the stent; 
 wherein the second mandrel component is made from a nonconductive material or coated with a nonconductive material, so that the electric field extending from the outermost surface is formed from ionized composition collected on the outermost surface. 
 
     
     
       16. A method for applying a composition to a stent, comprising the steps of:
 applying a charge to the stent and/or grounding the stent; 
 ionizing a composition; 
 disposing a first mandrel component within a bore of the stent, the first mandrel component having an outermost surface spaced from and exposed to a luminal surface of the stent and an electric field extending from the outermost surface and having the same polarity as the ionized composition; 
 spraying the stent with the ionized composition including limiting or preventing composition from coating the luminal surface of the stent by the electric field repelling the ionized composition; and 
 spraying the mandrel component with the ionized composition before disposing the mandrel component within the bore of the stent.